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First application of the local ensemble tangent linear model (LETLM) to a realistic model of the global atmosphere
S Frolov, DR Allen, CH Bishop, R Langland, KW Hoppel, DD Kuhl
Monthly Weather Review | AMER METEOROLOGICAL SOC | Published : 2018
Abstract
The local ensemble tangent linear model (LETLM) provides an alternative method for creating the tangent linear model (TLM) and adjoint of a nonlinear model that promises to be easier to maintain and more computationally scalable than earlier methods. In this paper, we compare the ability of the LETLM to predict the difference between two nonlinear trajectories of the Navy's global weather prediction model at low resolution (2.5° at the equator) with that of the TLM currently used in the Navy's four-dimensional variational (4DVar) data assimilation scheme. When compared to the pair of nonlinear trajectories, the traditional TLM and the LETLM have improved skill relative to persistence everywh..
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Awarded by Office of Naval Research
Funding Acknowledgements
This work was funded by the U.S. Office of Naval Research. Sergey Frolov and Craig H. Bishop acknowledge support from the Naval Research Base Program PE-0601153N. Douglas R. Allen and Karl W. Hoppel acknowledge support from Office of Naval Research base funding via Task BE-033-02-42. David D. Kuhl and Karl W. Hoppel acknowledge support from Office of Naval Research base funding via Task BE-435-050. Authors thank Philippe Lopez of ECMWF for useful feedback. All are grateful for the access to the Department of Defense high-performance computing resources that enabled us to conduct this research. We also thank three anonymous reviewers for the most thorough review of our manuscript.